Lifting jack with traveling pawl mechanism



Feb. 6, 1934. L, D. NlLsoN LIFTING JACK WITH TRAVELING PAWL MECHANISMFiled July 25, 1932 2 Sheets-Sheet 1 Feb. 6, 1934. L D. NlLsON LIFTINGJACK WITH TRAVELING PAwL MECHANISM Filed July 25, 1932 2 Sheets-Sheet 2-Patented Feb. 6, 1934 UNITED STATES LIF'rING JACK WITH 'rRAvELING rAwLMEoHANIsM i Leonard D. Nilsen, Wayzata, Minn. Application July 25,1932.Serial No. 624,624 15 Claims. (Cl. 254-2) An object of my presentinvention is to provide a simple and durable lifting jack with a pawlmechanism which travels along a ratchet bar for the purpose of impartinglifting movement to a lifting head of the jack.

Still a further object is to provide a lifting jack comprising a frameand a lifting arm pivoted thereto and mechanism for imparting liftingmovement to the lifting arm comprising a stationary ratchet bar and atraveler thereon'carrying pawls which coact with the ratchet bar to movethe traveler relative thereto, the traveler being operatively connectedwith the lifting arm.

Still a further object is to provide a pair of ratchet hars and a pairof pawl means coacting therewith, the teeth of the ratchet bars beingstaggered whereby to reduce the required length of stroke of theoperating handle so that it can 'ce operated in close quarters.

Still a further object is to provide a hydraulic mechanism for holdingany lifting movement gained by the pawl mechanism and including a checkvalve. g

Still a further object is to provide release means for the jack whichopens the check valve and thereby permitsand controls descent of theliftf ing head without the necessity of actuating the operating handlefor lowering purposes as in the ordinary type of pawl jack. Y

Another object is to provide a settling pawl to prevent any possibilityof the hydraulic mechanism allowing the load to settle when once raised.

Still another object is to provide means for rendering the lifting andsettling pawls of the jack inoperative at the same time thatvthe checkvalve is opened so as to -permit lowering of the jack. v

With these and other objects in view my invention consists in theconstruction, arrangement and combination of the various parts of mydevice, whereby the objects contemplated are attained, as hereinaftermore fully Aset forth, pointed out in my claims, and illustrated in theaccompanying drawings, in which:

Figure 1 is a plan view of a liftingvjack embodying my invention. g

Figure 2 is a side elevation of the same, a part of a frame bar thereofbeing broken away.

Figure 3 is a longitudinal vertical sectional view on the line 3-3 ofFigure l.

Figure 4 is a sectional viewv on the line 4-4 of Figure 1 showing theparts on an enlarged sacle.

Figure 5 is an enlarged sectional View on the line 5 5 of Figure 3. Y

Figure 6 is a sectional view 'on theline'6-6 of Figure 1 showing thepawl release mechanism; and

Figure 7 is a similar view on the line "1 7 of Figure 1 showingadditional features of the pawl mechanism.

On the accompanying drawings, I have used the reference numerals 10 and12 to indicate 'front and rear wheels for supporting the jackYstructure. Side frames 14 connect with an axle 16 on which the wheels 10areA journalled. Side bars 18 are secured as at 20 to the side frames 14and connect with a rear cross member 22 in the ends of which the rearwheels 12 are swivelly mounted.

The side frames 14 support a pivot shaft 24-on which is pivoted liftingarms 26. The arms 26 carry a pin 28 to which a lifting head 30ispivoted.

The lifting head 30 has end arms 32 carrying pivots 34. Links 36 connectthe pivots 34with pivot bolts 38` on the side frames 14.

The links 36 serve to stabilize the head 30 or retain it level withrespect to the jack frame in all positions of the head. i u

`For imparting lifting movement to the lifting arm 26 and therebyraising the head 30 relative lto the jack frame, I provide the followingdescribed mechanism. A pair of ratchet bars 40 have their rear endsconnected with the cross member 22 and their forward ends connected witha cross member 42. A traveler 44 is adaptedto travel along the ratchetbars 40. The travelerg44 consists of longitudinally' arranged sideplates, transverse pins 46, 46' and 46 and rollers 48 and 50. Theroller48 is adapted to travel on a track bar 52 positioned between the ratchetbars 40. The rollers 50 are adapted to contact with the bottoms of theratchet bars and the track bar.

The traveler 44 is connected by links 54 with the lifting arms 26.Pivots 56 and 58 serve asa means of connection between the lifting arms26, the traveler 44 and the links 54. From the forefgoingdescription, itwill be seen that movement of the traveler 44 along the ratchet barstoward the front of the jack will impart raising movement to theliftinghead 30. In order to operate the jack, it is necessary to impartsuch movement to the traveler. This is accomplished vby thefollowingdescribed mechanism.

A yoke 60 is pivoted to the pin 56. The yoke 60 carries a notched sector62. Pivoted on a pin 64 carried by the yoke, I provide an operatinghandle 66. The handle 66 may be adjusted relative to theyoke 60 and maybe retained in any adjusted position relative thereto by a dog 68. Thedog 68 is normally retained in engagement with one of los the notches ofthe sector 62 by a spring 70 and a link 72. 'Ihe upper ends of thespring and link are connected with a release lever 74 which mayV [pairof lifting pawls 76. It will be noted that the ratchet bars have teethof substantially the same size which are staggered relative to eachother.

The pawls 76, however, are of equal-length and by this arrangement,oscillation of the pawls even half a tooth will cause lifting action ofthe jack because when one pawl 76 does lnot catch, then the other onewill.

It will now be obvious that the yoke can be oscillated by oscillatingthe handle 66 and this will cause step by stepI movement of the traveler44 in a left hand direction. To hold any lifting movement gained, Iprovide a hydraulic mechanism which I will now describe.

Pivoted on the cross member 42 is a hydraulic cylinder 78. A piston rod80 is slidable relative thereto. The piston rod 80 carries a Vpiston 82Within the cylinder 78. 'I'he piston rod 8G is pivoted to a pin 84carried by the lifting arms 26.

Within the piston rod 80 (see Figure 4).I provide a check valve 86 heldnormally seated by a spring 88. During lifting movement of the jack, thepiston will travel toward the left and oil from the left end of thecylinder 78 will pass through Y a port 90, abore 92 and past the checkvalve 86 into the right end of the cylinder 78.V The oil will be held bythe check valve 86 so as to prevent any return movement of the traveleras caused by a vload on the lifting head tending to lower the head. Y

'Io guard against any settling of the load and to eliminate the entirestrain of holding the load being imposed on the hydraulicv mechanism Iprovidersettling pawls 94 pivoted on the pin 46. These are adapted toengage the-teeth of the ratchet bars 40.

In order to lower the jack, it is necessary to disengage the pawls '76and 94 andopen the check valve 86. To accomplish this, I provide arelease handle 98 connected by a cable 100 with an arm 102 of the pin 46and with the check valve as will be described. The cable 100 extendsunder a pulley 104 mounted on a pin 106 carried by the handle 66.

The cable has a collar 108 adapted to engage an eye member 119 of thelever 102 through which the cable extends. When the handle `98 is'pulled outwardly, the pin 46 will rock whereupon it will oscillate apair of pins 112 extending therefrom. The pins 112 engage pins 114extending from the settling pawls 94 for lifting them from the ratchetbars. f

Lifting of the near side holding pawl-will pull a rod 116 forwardlywhich will lift the near side lifting pawl 76. This pawl carries a pin118 which vengages a pin 120 extending from the pin 64. It will beobvious that Vlifting of the near side pawl '76 will therefore rotatethe pin 64. The pin 64 carries a second pin 122 which engages a pin 124extending from the far side lifting pawl 76. This will lift it from theratchet bar so that Vall four of the pawls will then be lifted.

As soon as they are lifted, the check valve 86 will be opened by furtheroutward swinging of the lever 98. This is accomplished through a bellcrank lever 126 which is connected with the forward end of the cable 100(see Figures 1 and 3) and which in turn is connected by a link 128 witha cam member 130. The cam member 130 is pivoted on the pin 84 andengages the forward end of a valve stem 132 (see Figure 4). It depressesthe valve stem so that the valve 86 will be forced away from its seatagainst the action of the spring 88. The amount the valve is open, ofcourse, will determine the speed of descent of the lifting head.

The pulley 104 is provided so that the lever 102 can be properlyoperated from the lever 98 regardless of the position of the operatinghandle 66 relative to the yoke 60. The bell crank lever 126 isprovided'so that the cam member 130 may be properly operated regardlessof the position of -the lifting head.

I have provided a jack structure in which by reason of staggering theratchet bar teeth, only slight oscillations of the operating handle arenecessary to impart lifting movement to the lifting head. It will beobvious, however, that the ratchet Vbar teeth could be made in alignmentand the length of one lifting pawl made a half tooth different than theother one to secure the same results. The operating handle can beadjusted so that it can be in any desired position or any positionrequired because of overhanging parts of the automobile. The slightoscillation necessary to operate the jack makes it especially desirablefor nat balloon tires when bumpers, trunks, etc. overhang the axles ofthe automobile. The hydraulic mechanism provides an effective means'for.holding any lifting movement gained and also as a flexible control forthe lowering movement of the jack. The speed of descent is entirelyunder the control of the operator and it is Vnot necessary for him towork the handle of the jack Vto `lower the lifting head as in mostratchet types of jacks.

Some changes may be made in the construction and arrangement of theparts of my device without departing from the real spirit and purpose ofmy invention, and it is my intention to cover by my claims, any modifiedforms of structure or use of Amechanical equivalents, which may bereasonably included within their scope.

I claim as my invention:

1. In a jack structure, a horizontal frame, a lifting arm pivotedthereto, a lifting head carried by said lifting arm and means forimparting lifting movement to said lifting arm comprising a ratchet barstationary on said frame and extending longitudinally thereof, a'traveler movable longitudinally of said ratchet bar and operativelyconnected with said lifting arm and pawl means on said traveler toimpart movement thereto.

lifting arm pivoted thereto, a lifting head carried by said lifting armand means for imparting lifting movement to said bar stationary on saidframe and longitudinally arranged relative thereto, va traveler lmovablelongitudinally of said bar, a link for operatively connecting saidtraveler with said lifting arm vand means for moving said travelerrelative to said bar.

3. In a jack structure, a horizontal frame, a lifting arm pivotedthereto, a lifting head carried by said lifting arm and means forimparting lifting movement to prising a ratchet bar stationary on andlongitudinal of said frame, a traveler movable longitudinally of saidratchet bar and operatively connected with said lifting arm, hydraulicmechanism for preventing lowering of said lifting head 2. In a jackstructure, a horizontal frame, ar

pas.

lifting arm comprising a said lifting arm comand pawl means on saidtraveler to impart movement thereto in a direction for raising saidlifting head.

4. In a jack structure, a horizontal frame, a lifting head raisablerelative thereto and means for imparting raising movement to saidlifting head comprising a ratchet bar lengthwise of and stationary onsaid frame, a traveler movable longitudinally thereof and operativelyconnected with said lifting head and pawl means for imparting movementto said traveler.

5. In a jack structure, a relatively long frame, a lifting head raisablerelative thereto, means for imparting raising movement to said liftinghead comprising a ratchet bar stationary on and lengthwise of saidframe, a traveler movable longitudinally thereof and operativelyconnected With said lifting head and pawl means for imparting movementto said traveler in a direction to raise said lifting head and hydraulicmechanism to prevent return movement of said traveler.

6. In a jack structure, a relatively long frame, a lifting head raisablerelative thereto, means for imparting raising movement to said liftinghead comprising a ratchet bar stationary on and lengthwise of saidframe, a traveler movable longitudinally thereof and operativelyconnected with said lifting head and pawl means for imparting movementto said traveler in a direction to raise said lifting head and hydraulicmechanism to prevent return movement of said traveler, said hydraulicmechanism including a check valve.

7. In a jack structure, a frame, a lifting head raisable relativethereto, means for imparting raising movement to said lifting headcomprising a ratchet bar stationary on said frame, a traveler movablelongitudinally thereof and operatively connected with said lifting headand pawl means for imparting movement to said traveler in a direction toraise said lifting head, hydraulic mechanism to prevent return movementof said traveler, said hydraulic mechanism including a check valve andcommon means for releasing said pawl means from said ratchet bar andopening said check valve to permit lowering of said lifting head.

8. In a jack structure, a horizontal frame, a lifting head raisablerelative thereto and means for imparting raising movement to saidlifting head comprising plural ratchet bar means stationary on andlengthwise of said frame, a traveler movable longitudinally of saidratchet bar means and operatively connected with said lifting head andplural pawl means coacting with said plural ratchet bar means for movingsaid traveler.

9. In a jack structure, a frame, a lifting head raisable relativethereto and means for imparting raising movement to said lifting headcomprising plural ratchet bar means stationary on said frame, a travelermovable longitudinally of said ratchet bar means and operativelyconnected with said lifting head and plural pawl means coacting withsaid plural ratchet bar means for moving said traveler, said pluralratchet bar means having staggered teeth where by movement of said pawlmeans less than a full tooth of any one of said ratchet bar means willcause step by step movement of said traveler along said ratchet barmeans.

10. In a jack structure, a frame, a lifting head raisable relativethereto and means for imparting raising movement to said lifting headcomprising a pair of ratchet bars having `teeth in staggered relation toeach other, said pair of ratchet bars being stationary relative to saidframe, a traveler movable longitudinally of said bars and operativelyconnected with said lifting head and pawl means for imparting movementto said traveler.

11. In a jack structure, a horizontal frame, a lifting head raisablerelative thereto and means for raising said lifting head comprising ahorizontal, straight, stationary ratchet bar, a movable traveler, saidtraveler being operatively connected with said lifting head for raisingit when said traveler moves in one direction relative to said ratchetbar and pawl means carried by said traveler to cause such movementthereof.

12. In a jack structure, a frame, a lifting head raisable relativethereto, means for raising said lifting head comprising a stationaryratchet bar, a movable traveler, said traveler being operativelyconnected with said lifting head for raising it when said traveler movesin one direction relative to said ratchet bar, pawl means carried bysaid traveler and directly coacting with said ratchet bar to cause suchmovement thereof and hydraulic mechanism to normally prevent reversemovement of said traveler.

13. In a jack structure, a frame, a lifting head raisable relativethereto, means for raising said lifting head comprising a stationaryratchet bar, a movable traveler, said traveler being operativelyconnected with said lifting head for raising it when said relative tosaid ratchet bar and pawl means carried by said traveler and directlycoacting with said ratchet bar to cause such movement thereof, hydraulicmechanism to normally prevent reverse movement of said traveler andvalve means to permit such reverse movement.

14. In a jack structure a frame, a lifting head raisable relativethereto, means for raising said lifting head comprising a stationaryratchet bar a movable traveler, said traveler being operativelyconnected with said lifting head for raising it when said traveler movesin one direction relative to said ratchet bar and pawl means carried bysaid traveler and directly coacting with said ratchet bar to cause suchmovement thereof, hydraulic mechanism to normally prevent reversemovement of said traveler, valve means to permit such reverse movementand a single means for both releasing said pawl means and opening saidvalve means.

15. In a jack structure, a frame, a lifting head raisable relativethereto, means for raising said lifting head comprising a stationaryratchet bar, a movable traveler, said traveler being operativelyconnected withv said lifting head for raising it when said travelermoves in one direction relative to said ratchet bar and pawl meanscarried by said traveler and directly coactable with said ratchet bar tocause such movement thereof, hydraulic mechanism to normally preventreverse movement of said traveler and a pawl to prevent settling of saidhydraulic mechanism and said lifting head.

LEONARD D. NILSON.

traveler moves in one direction i list

